Novel concept of functional oxide coatings providing enhanced oxidation resistance to Ni-based superalloys

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2013.09.017· OSTI ID:22341879

Pedraza, F., E-mail: [e-mail]; Balmain, J., E-mail: [e-mail]; Bonnet, G., E-mail: [e-mail]; Bouchaud, B., E-mail: [e-mail]

Graphical abstract: - Highlights: • New concept for providing extended oxidation resistance to Ni-based superalloys. • Oxygen-defective nanostructured oxide coatings reduce the oxygen partial pressure at the substrate interface. • Pre-oxidation of the substrate during annealing with the formation of alpha-alumina. • Growth of CeAlO{sub 3} perovskite enhancing the adherence of the ceria top coat. • Microstructural stability of the coating system with no SRZ formation upon exposure. - Abstract: Aluminide-coated Ni-based superalloys are prone to microstructural instabilities during long-term exposure at high temperature with the growth of a secondary reaction zone (SRZ) detrimental from a mechanical viewpoint. This has been since overcome by the use of thermodynamically stable coatings (γ-Ni/γ′-Ni{sub 3}Al). However, additions of Pt and Hf are required to provide the formation of an exclusive α-Al{sub 2}O{sub 3} scale and improved oxidation resistance in cyclic and isothermal regimes. The present work proposes a new coating system that relies on the use of a superficial nanostructured functional oxide providing the establishment of a stable alumina while avoiding SRZ formation. Tailored oxygen-defective and multi-cracked coatings were designed for 2nd generation Ni-based superalloys and generated by electrosynthesis using a water-based solution. Cyclic oxidation tests were carried out at 1100 °C in air and the oxidation properties and the microstructural stability of the coating system were demonstrated.

• OSTI ID: 22341879
• Journal Information: Materials Research Bulletin, Vol. 49; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
ANNEALING
CERIUM OXIDES
COATINGS
DEFECTS
HEAT RESISTING ALLOYS
MICROSTRUCTURE
NANOSTRUCTURES
OXIDATION
OXYGEN
PARTIAL PRESSURE
PEROVSKITE
RAMAN SPECTROSCOPY
SUBSTRATES